Track-type machines, for example dozers, excavators, and skid-steer loaders, are commonly used in applications where traction is critical or low ground pressure is important. These machines include a frame that supports an internal combustion engine, and left and right undercarriages that transfer power from the engine to a ground surface. The left and right undercarriages are rigidly mounted at one end to the frame and free to pivot in a vertical direction about the mounting location. Each of the undercarriages includes a final drive with a sprocket at the proximal end that is driven by the engine, and an idler wheel located at the distal end and operatively connected to the sprocket via an idler frame assembly. The idler frame assembly includes a plurality of upper carrier rollers and lower rollers that support an endless track wrapped in a loop around the sprocket and idler. The rollers each contain mechanical face seals that inhibit foreign materials from entering and lubricating fluid from exiting an interior of the roller.
In some instances, debris in the environment of the machine may enter a passageway extending into an interior of a roller and reach the mechanical face seals. The debris may pack into the seal cavity and obstruct the seal, allowing lubricating fluid to escape and/or preventing proper rotation of the roller, causing the roller to fail. For example, during use of a track-type machine in landfill applications, wire, rope, and/or other trash debris may find its way into the passageway, reach the seal, and cause the roller to fail. In other instances, materials such as dirt, sand, and clay may build up in and around the seal and cause failure.
One attempt to protect a mechanical face seal of a track-type machine is disclosed in U.S. Pat. No. 8,356,680 that issued to Jackson on Jan. 22, 2013 (“the '680 patent”). In particular, the '680 patent discloses a guard ring positioned to cover an opening into a seal protection passageway that leads to the seal of a final drive assembly of the track-type machine. The guard ring is bolted to a fixed hub and defines a labyrinth interface with a rotating sprocket hub. The labyrinth interface includes a tortuous pathway for inhibiting debris from entering the seal protection pathway. The guard ring also defines a drain passage that allows liquid debris that makes its way inside the guard ring to flow out.
Another attempt to protect a mechanical face seal of a track-type machine includes a pair of bolt-on rings that surround the seal of a final drive assembly. One of the bolt-on rings is a stationary guard ring that includes a plurality of enlarged openings that provide direct communication with the seal. The openings may extend around at least a lower half of the guard ring and may be large enough such that debris (e.g., dirt, mud, etc) that enters an opening may fall back out via gravity.
Although the guard rings described above may help inhibit debris from causing failure of mechanical face seal of a final drive assembly, they may suffer from some drawbacks. For example, while the labyrinth interface of the guard ring of the '680 patent may inhibit some debris from reaching the seal, fine debris such as dirt and sand may pack in the labyrinth passages and hinder relative rotation of the fixed hub and sprocket hub. Further, while the drain passage of the guard ring of the '680 patent may allow liquid debris to escape once inside, solid debris that does make its way into the guard ring may be trapped, allowing debris to build up and eventually reach the seal and/or damage the guard ring. Regarding the bolt-on guard ring described above, while the openings may allow fine debris to fall out via gravity, the openings may also provide direct access to the seal for larger debris to cause damage. Further, each of the guard rings described above are configured for protecting a final drive assembly and may not be configured for protection of track rollers and idlers, which include different geometries, features, and configurations of fixed and rotating components.
The present disclosure is directed to overcoming one or more of the problems set forth above and/or other problems of the prior art.